WASHINGTON — The stream of terror threat reports, which have dogged the run-up to the Sochi Olympic Winter Games, are expected to continue in the two weeks before opening ceremonies next month, U.S. government authorities said Friday.

A memo sent by the U.S. Olympic Committee also advised the contingent of 230 American athletes not to display identifying clothing or colors outside of secure, accredited areas.

The direction to the athletes was described by senior administration officials Friday in background security briefing for reporters. The officials requested anonymity to discuss the continuing concerns related to Olympic security in Russia.

"We have seen an uptick in threat reporting,'' one of the officials said, adding that the U.S. government was "paying close attention. We take all such threats seriously.''

Although the officials said that Russian authorities were cooperating with their U.S. counterparts in connection with the security preparations, the officials acknowledged that they had only learned of the Russian government's recent dragnet in the Sochi area for possible terror suspects, including a suspected female suicide bomber, through media reports.

"We are frustrated that we don't know everything,'' one of the officials said, adding that the frustration was not directed at the Russian government.

The specter of terror has long shrouded the Sochi Winter Games because of the host city's proximity to a hot bed of Islamic extremist activity in the North Caucasus region. And the terror fears have intensified in the past month after suicide bombing attacks in the city of Volgograd left more than 30 people dead, nearly 500 miles from Sochi.

The administration officials described security as "the highest priority'' for the U.S. team, the official delegation and American visitors, which could number about 10,000 during the games.

In addition to thousands of Russian security forces, the administration officials said teams of U.S. diplomatic security agents would accompany American athletes to the event sites scattered from the Black Sea coast to the mountains.

Asked to elaborate on the guidance provided to American athletes regarding the display of identifying clothing, one of the officials said: "It's reasonable advice.''

The USOC memo, which was obtained by USA TODAY Sports, cautioned athletes about gear outside the secured Olympic zone: "The U.S. Department of State has advised that wearing conspicuous Team USA clothing in non-accredited areas may put your personal safety at greater risk."

The officials said U.S. authorities have established a joint operations center in the Sochi area to monitor developments and assess the credibility of potential threats.

State and Defense department officials also are involved in contingency planning in the event of a possible security crisis. But the officials said Friday there were "no specific evacuation plans on the shelf ready to pull off'' in the event of an emergency.

Earlier this week, Pentagon spokesman Rear Admiral John Kirby said ships were being deployed to the Black Sea.

"The ships that we're going to putting in the Black Sea are ships that -- that have by design multiple capabilities, as most of our ships do,'' Kirby said. "And most of our ships are capable of helicopter lift. Most of our ships have some sort of medical facility onboard. Most of our ships have the ability to either command and control assets or at least to communicate with other assets.''

But Kirby declined to elaborate on the deployment.

"I don't want to get into the specific details there,'' he said. "There's been no mission assigned to them, either, no specific mission with respect to the Olympics, that is."